1. Field of the Invention
This invention is concerned with the breaking or resolution of oil-in-water (O/W) bituminous emulsions by treatment with cationic polymers.
2. Description of Related Art
A great volume of hydrocarbons exist in known deposits of tar sands. These deposits occur at various places, the Athabasca tar sands in Canada being an example. The petroleum in a tar sand deposit is an asphaltic bitumen of a highly viscous nature ranging from a liquid to a semisolid. These bituminous hydrocarbons are usually characterized by being very viscous or even non-flowable under reservoir conditions by the application of driving fluid pressure.
Where surface mining is not feasible, the bitumen must be recovered by rendering the tar material mobile in-situ and producing it through a well penetrating the tar sand deposit. These in-situ methods of recovery include thermal, both steam and in-situ combustion and solvent techniques. Where steam or hot water methods are used, a problem results which aggravates the recovery of the bitumen. The difficulty encountered is emulsions produced by the in-situ operations. These emulsions are highly stable O/W emulsions which are made even more stable by the usual presence of clays. Most liquid petroleum emulsions are water-in-oil (W/O) types. These normal W/O emulsions are broken by methods known in the art. However, the bitumen emulsions which are O/W types present a much different problem, and the same demulsifiers used in W/O emulsions will not resolve the O/W bitumen emulsions. The following is a list of art references.
A. C. W. W. Gewers, J. Canad. Petrol. Tech., 7(2), 85-90 (1968) describes the uniqueness of emulsions encountered in the production of bitumen from tar sands.
B. U.S. Pat. No. 4,252,746 discloses the composition used in the present invention.
C. U.S. Pat. No. 4,058,453 (Texaco) describes the use of poly(ethylene oxides) of &gt;1 million molecular weight for breaking bitumen emulsions.
D. U.S. Pat. No. 3,296,117 (Esso) claims a tar demulsifier system consisting of (1) diethylethanolamine polyalkoxylate plus (2) palmitic acid ester of an ethoxylated alkylphenol-formaldehyde adduct.
E. U.S. Pat. No. 3,782,472 (Petrolite) reveals the use of amino alkoxylates as demulsifiers for steam injection into sub-surface oil-producing formations and subsequent hydrocarbon recovery.
F. Various cationic flocculants are claimed in the literature including epichlorohydrin (ECH) adducts with
1. Lower secondary amines (U.S. Pat. Nos. 3,738,945 and 3,894,944) PA2 2. Lower secondary amines plus polyalkylenepolyamine or polypropoxydiamine (U.S. Pat. No. 3,738,945) PA2 3. Linear polyalkylene polyamines (U.S. Pat. No. 3,523,892) PA2 4. Polyalkylenepolyamines plus alkylene dihalides (British Pat. No. 1,096,964) PA2 5. Lower primary monoamines (U.S. Pat. No. 3,493,502).
G. U.S. Pat. No. 4,029,078--Demulsifiers prepared by reacting epichlorohydrin with the 8 mole propoxylate of H.sub.2 N(CH.sub.2).sub.6 NH.sub.2.
H. U.S. Pat. No. Re. 29,908 (Betz)--Oil separated from oil-containing wastewater using polymer of ECH and ##STR1## where R=alkyl and R'=alkylene.
I. U.S. Pat. No. 3,251,882 (Nalco)--O/W emulsions broken by polymers from ECH plus a condensate of a polyalkylene polyamine and a poly(oxyalkylene) glycol chloride.
J. U.S. Pat. No. 3,251,882 (Nalco)--O/W emulsions broken by polymers from (a) ECH and polyalkylene polyamines, and (b) ECH and aliphatic glycols.
K. U.S. Pat. No. 3,251,882 (Nalco)--O/W emulsions broken by polymers from ECH, ECH adduct of an aliphatic glycol, and a polyalkylene polyamine.
L. U.S. Pat. No. 3,205,169--O/W emulsions broken using an adduct of ECH plus dipropylenetriamine plus C.sub.12-18 primary amines.
M. U.S. Pat. No. 3,272,757--O/W emulsions broken using adducts of ECH plus polyalkylene polyamines.
N. U.S. Pat. No. 3,591,520--O/W emulsions broken using adducts of poly(epichlorohydrin), trimethylamine, and ethoxylated dimethylamine.
O. U.S. Pat. No. 3,900,423--O/W or W/O emulsions broken with adducts of ECH plus primary alkylamines or alkylenpolyamines plus secondary alkylamines or alkylene polyamines having 1-6 secondary amine groups per molecule.